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Wyszukujesz frazę "Rahman, A." wg kryterium: Autor


Tytuł:
Gender differences of managing banks’ credit portfolio
Różnice płci w zarządzaniu portfelem kredytowym banków
Autorzy:
Rózsa, Z.
Zbranková, H.
Rahman, A.
Powiązania:
https://bibliotekanauki.pl/articles/406040.pdf
Data publikacji:
2018
Wydawca:
Politechnika Częstochowska
Tematy:
credit risk management
gender
ethics
behaviour
banks
zarządzanie ryzykiem kredytowym
płeć
etyka
zachowanie
banki
Opis:
The article aimed to demonstrate whether the quality of decision-making on lending to clients in the small and medium-sized business sector is influenced by the gender of the approvers or their direct motivation caused by share on business results. The motivation for this research were the studies conducted after the last global financial crisis, mostly in the US and Europe, to a lesser extent in the Czech Republic. Their authors tend to conclude that women show better credit risk management than men and that direct managers’ engagement in business results and profits generates a higher susceptibility to risky, erroneous decisions. The research was carried out on one of the major banks operating in the Czech Republic, on a nationwide sample of workers with the loan approval authority in the segment of small and medium-sized firms. The decision of the approvers was, based on a random selection of about 1/3 of all their decisions, subject to control over three consecutive years. The obtained data were analysed by ANOVA, which did not prove the dependence of the decision quality on the gender or the direct motivation of the approver on business results. The research and its results have opened up scope for further research on the issue with a focus on a qualitative analysis of the nature and severity of the mistakes in terms of gender, job position, the level of authorization power and, last but not least, the unequal representation of women in the management of domestic banks.
Artykuł miał na celu wykazanie, czy na jakość procesu decyzyjnego w zakresie udzielania kredytów klientom w sektorze małych i średnich przedsiębiorstw wpływa płeć osób zatwierdzających lub ich bezpośrednia motywacja spowodowana udziałem w wynikach biznesowych. Motywacją do tych badań były badania przeprowadzone po ostatnim światowym kryzysie finansowym, głównie w USA i Europie, w mniejszym stopniu w Czechach. Ich autorzy mają tendencję do stwierdzenia, że kobiety wykazują lepsze zarządzanie ryzykiem kredytowym niż mężczyźni i że bezpośrednie zaangażowanie menedżerów w wyniki biznesowe i zyski generuje wyższą podatność na ryzykowne, błędne decyzje. Badania przeprowadzono w jednym z największych banków działających w Republice Czeskiej, w ogólnokrajowej próbie pracowników z organem zatwierdzającym pożyczki w segmencie małych i średnich firm. Decyzja osób zatwierdzających była oparta na losowej selekcji około 1/3 wszystkich decyzji, podlegających kontroli przez trzy kolejne lata. Uzyskane dane zostały przeanalizowane przez ANOVA, która nie wykazała zależności jakości decyzji od płci ani bezpośredniej motywacji osoby zatwierdzającej do wyników biznesowych. Badania i ich wyniki otworzyły możliwości dalszych badań w tym zakresie, koncentrując się na jakościowej analizie charakteru i wagi błędów pod względem płci, stanowiska pracy, poziomu uprawnień do autoryzacji oraz, co nie mniej ważne, nierówna reprezentacja kobiet w zarządzaniu bankami krajowymi.
Źródło:
Polish Journal of Management Studies; 2018, 18, 2; 272-283
2081-7452
Pojawia się w:
Polish Journal of Management Studies
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Properties of~Rf Plasma Nitrided Silicon Thin Films at Different Rf Plasma Processing Powers
Autorzy:
Mohamed, S.
Raaif, M.
Abd El-Rahman, A.
Shaaban, E.
Powiązania:
https://bibliotekanauki.pl/articles/1493713.pdf
Data publikacji:
2011-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.15.Dj
61.05.cp
73.61.-r
78.66.-w
Opis:
Nitrided surfaces and composition gradients in thin films exhibit interesting mechanical, electrical and optical properties. Therefore, silicon (Si) thin films were prepared by electron beam evaporation and nitrided by an inductively coupled rf plasma. The effects of successive plasma processing power on structural and optical properties as well as electrical resistivity were examined by different characterization techniques. The Si thin films were transformed gradually into nitrides compound thin films and the amount of nitrogen in the film increased with increasing the rf processing power. The Si nitrided films showed structural, optical and electrical properties that depend on the nitriding power. Increasing the rf plasma processing power caused amorphization, reduced the thickness, increased transmittance, increased resistivity and decreased the reflectance of the Si films. The electrical resistivity increased about eight orders of magnitude when the sample nitrided at 500 W. Different optical band gap were determined indicating the presence of different competing phases in the same film. The decrease in refractive index with plasma treatment power is attributed to the possible change in the bucking density as well as to the increase in the band gap.
Źródło:
Acta Physica Polonica A; 2011, 120, 3; 552-557
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
EDTA reduces cadmium toxicity in mustard (Brassica juncea L.) by enhancing metal chelation, antioxidant defense and glyoxalase systems
EDTA obniża toksyczność kadmu w gorczycy sarepskiej (Brassica juncea L.) poprzez zwiększenie chelatowania metalu oraz poprawę działania systemu antyoksydacyjnego i glioksalazowego
Autorzy:
Al Mahmud, J.
Hasanuzzaman, M.
Nahar, K.
Rahman, A.
Fujita, M.
Powiązania:
https://bibliotekanauki.pl/articles/27056.pdf
Data publikacji:
2019
Wydawca:
Polskie Towarzystwo Botaniczne
Opis:
To investigate the possible role of EDTA in mitigating cadmium (Cd) toxicity, we treated mustard (Brassica juncea L.) seedlings with CdCl2 (0.5 mM and 1.0 mM, 3 days) alone and in combination with 0.5 mM EDTA in a semihydroponic medium. In the absence of EDTA, mustard seedlings accumulated Cd in their roots and shoots in a concentration dependent manner. Overaccumulation of Cd boosted generation of hydrogen peroxide (H2O2) and superoxide anions (O2•−), increased lipoxygenase (LOX) activity, lipid peroxidation, and cytotoxic methylglyoxal (MG) content. It also disturbed components of the antioxidant defense and glyoxalase systems. Furthermore, Cd stress decreased growth, leaf relative water content (RWC) and chlorophyll (chl) content but augmented the proline (Pro) content. On the other hand, EDTA supplemented Cd-stressed seedlings improved the constituents of the AsA-GSH cycle with the upregulated activities of ascorbate peroxidase (APX), monodehydroascorbate reductase (MDHAR), dehydroascorbate reductase (DHAR), glutathione reductase (GR), glutathione peroxidase (GPX), superoxide dismutase (SOD), and catalase (CAT). Moreover, addition of EDTA to the Cd-stressed seedlings notably enhanced Gly I activity in contrast to the stress treatment. Ethylenediaminetetraacetic acid decreased Cd accumulation in the both shoots and roots, as well as increased other nonprotein thiols (NPTs) in leaves, including the phytochelatin (PC) content. It also decreased H2O2 and O2•− generation, lipid peroxidation and MG content but enhanced RWC, chl and Pro contents in the leaves, which confirmed the improved growth of seedlings. The findings of the study suggest that exogenous application of EDTA to the Cd-treated seedlings reduces Cd-induced oxidative injuries by restricting Cd uptake, increasing NPTs concentration and upregulating most of the components of their antioxidant defense and glyoxalase systems.
W celu określenia roli EDTA (kwas edetynowy, acidum edeticum) w obniżaniu toksyczności kadmu (Cd), siewki gorczycy (Brassica juncea L.) traktowano CdCl2 (w stężeniach 0,5 i 1 mM przez 3 dni) w kombinacjach z lub bez dodatku 0,5 mM EDTA do semi-hydroponicznego podłoża. Rośliny uprawiane w obecności Cd bez EDTA akumulowały metal w korzeniach i częściach nadziemnych proporcjonalnie do zastosowanego stężenia Cd. Akumulacja Cd indukowała produkcję nadtlenku wodoru (H2O2) i anionu ponadtlenkowego (O2•−), zwiększała aktywność lipoksygenazy (LOX), peroksydację lipidów i poziom cytotoksycznego metyloglioksalu (MG). Kadm zakłócał również funkcjonowanie składników systemu antyoksydacyjnego i glioksalazowego. Ponadto, Cd negatywnie wpływał na wzrost roślin, względną zawartość wody w liściach (RWC) i stężenie chlorofilu, ale stymulował akumulację proliny (Pro). Dodatek EDTA do pożywki zawierającej Cd pozytywnie wpływał na funkcjonowanie cyklu glutationowo-askorbinianowego, zwiększając aktywność peroksydazy askorbinianowej (APX), reduktazy monodehydroaskorbinianowej (MDHAR), reduktazy dehydroaskorbinianowej (DHAR), reduktazy glutationowej (GR), peroksydazy glutationowej (GPX), a także dysmutazy ponadtlenkowej (SOD) i katalazy (CAT). Ponadto, dodanie EDTA do środowiska wzrostu roślin traktowanych Cd zwiększyło aktywność glioksalazy I (Gly I) w roślinach, czego nie stwierdzono w roślinach traktowanych wyłącznie Cd. EDTA ograniczył akumulację Cd zarówno w korzeniach, jak i w częściach nadziemnych, zwiększając jednocześnie poziom niebiałkowych tioli (NPT), w tym fitochelatyn (PC). Dodatkowo, w roślinach traktowanych Cd w obecności EDTA stwierdzono niższy poziom H2O2, O2•− i MG oraz obniżenie peroksydacji lipidów, ale wzrost RWC, a także stężenia chlorofilu i Pro, co wpłynęło na lepszy wzrost roślin. Uzyskane wyniki sugerują, że zastosowanie egzogennego EDTA razem z Cd obniża toksyczność metalu związaną z generowaniem stresu oksydacyjnego, poprzez ograniczenie pobierania Cd, zwiększenie stężenia NPT i pozytywny wpływ na aktywność większości składników systemu antyoksydacyjnego i glioksalazowego.
Źródło:
Acta Agrobotanica; 2019, 72, 2
0065-0951
2300-357X
Pojawia się w:
Acta Agrobotanica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Serodiagnosis of Toxoplasmosis using Lateral Flow Chromatographic Immunoassay among Animals and Humans in Sunsari District of Nepal
Autorzy:
Sah, Ramesh Prasad
Talukder, Md Hasanuzzaman
Rahman, A. K. M. Anisur
Powiązania:
https://bibliotekanauki.pl/articles/1167051.pdf
Data publikacji:
2018
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Animals
Nepal
human
seroprevalence
toxoplasmosis
Opis:
Toxoplasmosis is a cosmopolitan parasitic zoonosis, infecting human and other warm blooded animals worldwide. This disease has economic importance in regard to animal reproduction, and it leads to abortions and neonatal complications in humans. This study was carried out to determine the seroprevalence of Toxoplasma gondii in sheep, cattle, cats and human in Inaruwa and surrounding areas of Sunsari district, Nepal. Altogether 336 blood samples, of which 50 from sheep, 92 from cattle, 44 from cats and 150 from human were collected and tested immediately using lateral flow chromatographic immunoassay (Toxo IgG/IgM Combo Rapid test®). Associated biometric information such as age, sex, pregnancy status, occupation, association with cat was recorded and analyzed to determine the association of risk factors with the disease. Data were analyzed using R 3.2.2 (The R foundation for Statistical Computing, 2015). Seroprevalence of toxoplasmosis was detected 12.00% (95% CI: 4.53- 24.31%) in sheep, 8.70% (95% CI: 3.83- 16.42%) in cattle, 36.36% (95%CI: 22.41- 52.23%) in cats and 12.67% (95% CI: 7.80- 19.07%) in human. In case of human, 31 to 45 years age group were found more susceptible to toxoplasmosis (21.74%, OR: 6.4) in comparison to 21 to 30 years (10.0%) and up to 20 years (4.17%) age groups. Toxoplasmosis was found highly significantly associated with abortion (58.33%, OR= 15.4, P=0.0001) in human in the tested individuals. Regarding occupation, 20.83% butchers were seropositive followed by farmers (15.52%), housewives (10.0%) and diagnostic lab technicians (8.0%). Female and higher age group showed high prevalence of toxoplasmosis in all studied species. Therefore, this assay is a useful method for the serological screening of toxoplasmosis in different animals and humans.
Źródło:
World Scientific News; 2018, 105; 145-156
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of heat treatment on microhardness of electroless Ni-YSZ cermet coating
Autorzy:
Bahiyah Baba, N.
Ghazali, A. S.
Abdul Rahman, A. H.
Sharif, S.
Powiązania:
https://bibliotekanauki.pl/articles/2201036.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
Ni-YSZ
cermet
coating
microhardness
heating temperature
heating time
electroless nickel
powłoka
mikrotwardość
temperatura nagrzewania
czas nagrzewania
bezprądowe powlekanie niklem
Opis:
Purpose: The paper discussed the effect of heat treatment on electroless nickel-yttria-stabilised zirconia (Ni-YSZ) cermet coating. Ni-YSZ cermet coating has potential applications such as cutting tools, thermal barriers, solid oxide fuel anode, and various others. The compatibility of ceramic YSZ and metallic nickel in terms of the mechanical properties such as hardness by varying the heating temperature, time and ceramic particle size is highlighted. Design/methodology/approach: Ni-YSZ cermet coating was deposited onto a highspeed steel substrate using the electroless nickel co-deposition method. The temperature and time were varied in a range of 300-400°C and 1-2 hours, respectively. The microhardness measurements were carried out using a Vickers microhardness tester (Shimadzu) according to ISO 6507-4. The surface characterisation of the cermet coating was carried out using JOEL Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray (EDX) JSM 7800F. The crystallographic structure of materials was analysed by X-ray diffraction (XRD) Bruker D8 Advance instrument. Findings: It was found that the microhardness of Ni-YSZ cermet coating with the ratio of 70:30, respectively, is directly proportional to the heating temperature and time. Heating the Ni-YSZ cermet coating at 300°C from room temperature (rtp) to 1 hour shows a 12% microhardness increment, while from 1 to 2 hours gives a 19% increment. Compared to heating at 350°C and 400°C, the increment is more significant at 33% and 49% for rtp to 1 hour and 8% and 16% for 1 to 2 hours, respectively. In addition, the effect of varying YSZ particle size in the Ni-YSZ cermet gave response differently for heating temperature and heating time. Research limitations/implications: The paper is only limited to the discussion of the heat treatment effect on Ni-YSZ cermet coating hardness property. The tribological effect will be in future work. Practical implications: The microhardness data may vary due to the Vickers microhardness force applied and the amount of ceramic particle incorporation and phosphorus content in the nickel matrix. Originality/value: The value of this work is the compatibility of the ceramic YSZ and metallic nickel matrix in terms of mechanical properties, such as hardness, upon heat treatment.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 113, 1; 5--12
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Parametric optimisation of microhardness on heat-treated electroless Ni-YSZ cermet coating
Autorzy:
Bahiyah Baba, N.
Ghazali, A. S.
Abdul Rahman, A. H.
Sharif, S
Powiązania:
https://bibliotekanauki.pl/articles/2172165.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
full factorial
electroless
Ni-YSZ
cermet
coating
microhardness
treating temperature
treating time
silnia
bezprądowy
powłoka
mikrotwardość
temperatura obróbki
czas obróbki
Opis:
Purpose The paper discusses the parametric optimisation of the electroless Ni-YSZ cermet coating microhardness upon heat treatment. Heat treatment is a process to increase the mechanical properties of the electroless nickel coating and it can be enhanced by manipulating its parameters. Parametric optimisation is conducted by the design of experiment full factorial 3x3 with 27 runs. Treating temperature, treating time and ceramic particle size parameters at 3-level are evaluated using statistical tool ANOVA in Minitab20. Design/methodology/approach Ni-YSZ cermet coating is deposited onto a high-speed steel substrate using the electroless nickel co-deposition method. The temperature and time were varied in a range of 300-400oC and 0-2 hours respectively. The microhardness measurements were carried out using a Vickers microhardness tester (Shimadzu) according to ISO 6507-4. The surface characterisation was analysed using Cambridge Stereoscan 90 Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray Analysis (EDXA). Findings The optimum condition in obtaining high microhardness on Ni-YSZ cermet coating is evaluated by statistical tool ANOVA in Minitab20 software. It is found that the most significant parameter for high microhardness is at the treating temperature of 400oC followed by treating time at 2 hours using nano-sized YSZ particles. The ceramic particle size is found not a significant parameter in obtaining a high microhardness, however it has effect on interaction between treating temperature and treating time. Research limitations/implications The paper only limits to the optimisation condition of microhardness on Ni-YSZ cermet coating hardness property by varying heat treatment parameters. Practical implications The optimisation condition obtained might only applicable to the electroless Ni-YSZ cermet coating with similar electroless nickel solution and treatments. Originality/value The value of this work is the heat treatment parametric optimisation to obtain high microhardness on electroless Ni-YSZ cermet coating by using the design of experiment 3-level full factorial.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 112, 1; 33--41
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effect of particle size on surface roughness and morphology of heat-treated electroless Ni-YSZ coating
Autorzy:
Bahiyah Baba, N.
Ghazali, A. S.
Azinee, S. N.
Abdul Rahman, A. H.
Sharif, S.
Powiązania:
https://bibliotekanauki.pl/articles/2201055.pdf
Data publikacji:
2022
Wydawca:
Stowarzyszenie Komputerowej Nauki o Materiałach i Inżynierii Powierzchni w Gliwicach
Tematy:
particle size
electroless coatings
Ni-YSZ
heat treatment
surface roughness
surface morphology
wielkość cząstek
powłoka
powlekanie bezprądowe
obróbka cieplna
chropowatość powierzchni
morfologia powierzchni
Opis:
Purpose The paper discusses the surface characterisation of electroless nickel-yttria-stabilised zirconia (Ni-YSZ) coating with varying YSZ particle sizes and undergoes heat treatment at a temperature between 300-400°C for 1-2 hours for wear resistance purposes. This finding will be helpful to the application of Ni-YSZ as an alternative coating for cutting tools. Design/methodology/approach The surface characterisation was analysed using JOEL Scanning Electron Microscope (SEM) coupled with Energy Dispersive X-ray (EDX) JSM 7800F. The crystallographic structure of materials was analysed by X-ray diffraction (XRD) Bruker D8 Advance instrument. The Ni-YSZ coating was deposited using electroless nickel co-deposition of 8YSZ ceramic particles with a nano, mixed and microparticle sizes onto a high-speed steel (HSS) substrate. The coatings were heat treated at temperature 300-400°C and time 1-2 hours. The surface roughness was measured using Mitutoyo surface roughness tester SJ-301. Findings The electroless Ni-YSZ coating deposited has an average thickness of 30 µm. It is found that the coating morphology electroless coating without YSZ particle incorporation (EN) and Ni-YSZ nano (N) is smoother compared to the Ni-YSZ mixed (NM) and Ni-YSZ micro (M). The EDS composition analysis shows the YSZ content in the electroless Ni-YSZ coating for N samples is the lowest, whereas NM samples are the highest. This resulted in the surface roughness behaviour where the mixed-size YSZ particle gives the highest roughness at all temperatures. The XRD analysis shows that heating temperatures above 300°C caused the precipitation of Ni3P crystalline. Research limitations/implications Previous studies in the surface characterisation of electroless nickel composite are scarce; thus, the study has limitations in finding supporting data. Originality/value The surface characterisation especially related to the surface roughness of the electroless nickel, either the Ni-P or composites or alloys are rarely reported. Thus, this study enlightened the effect of particle size on surface roughness and morphology of heat-treated coatings.
Źródło:
Journal of Achievements in Materials and Manufacturing Engineering; 2022, 114, 1; 5--14
1734-8412
Pojawia się w:
Journal of Achievements in Materials and Manufacturing Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Friction and adhesion energy of polymer–polymer sliding combinations
Tarcie i energia adhezji podczas ślizgania w połączeniach polimer–polimer
Autorzy:
Marzouk, W. W.
Abdel-Rahman, M. A.
Powiązania:
https://bibliotekanauki.pl/articles/188045.pdf
Data publikacji:
2012
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
friction coefficient
reversible adhesion energy
hardness ratio
polymer–polymer pairs
współczynnik tarcia
energia adhezji
wskaźnik twardości
połączenie polimer–polimer
Opis:
The friction coefficient, reversible adhesion energy and hardness ratio of polymer-polymer combinations such as PC, PS, PTFE, PA6, LDPE and PP are examined using a pin-on-ring type tribometer. Polycarbonate has been used as a ring material. The applied loads are 10, 20, 30, 40, and 50 N. The coefficient of friction as a function of sliding time, applied load, and hardness ratio has been observed. Additionally, the relationship between the coefficient of friction and reversible adhesion energy calculated from the surface components is calculated. The results show that the coefficient of friction is highly dependent on the reversible energy. The coefficient of friction increases as the reversible adhesion energy increases. At a hardness ratio equal to unity, the coefficient of friction exhibits high values. At higher values of the hardness ratio, HC/Hp = 2.4, however, the coefficient of friction possesses low values. In addition, the coefficient of friction is highly dependent on the load applied. It decreases with the increase in the load.
W pracy przedstawiono wyniki badań współczynnika tarcia, odwracalnej energii adhezji i stosunku twardości połączeń polimer-polimer, takich jak PC, PS, PTFE, PA6, LDPE i PP, które określano przy użyciu testera typu trzpień–pierścień. Na materiał pierścienia wykorzystano poliwęglan. Zastosowano obciążenia 10, 20, 30, 40 i 50N. Obserwowano zmianę współczynnika tarcia w funkcji czasu ślizgania, przyłożonego obciążenia i wskaźnika twardości. Ponadto obliczano zależność pomiędzy współczynnikiem tarcia i odwracalną energią adhezji. Wyniki pokazują, że współczynnik tarcia jest bardzo zależny od energii adhezji. Współczynnik tarcia wzrasta wraz ze wzrostem energii adhezji. Przy jednakowej twardości materiałów współczynnik tarcia przyjmuje wysokie wartości. Przy wyższych wartościach wskaźnika twardości, HC/Hp = 2.4, współczynnik tarcia ma małą wartość. Dodatkowo, współczynnik tarcia bardzo zależy od przyłożonego obciążenia – jego wartość maleje wraz ze wzrostem obciążenia.
Źródło:
Tribologia; 2012, 5; 97-106
0208-7774
Pojawia się w:
Tribologia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The youngest ctenocystoids from the Upper Ordovician of the United Kingdom and the evolution of the bilateral body plan in echinoderms
Autorzy:
Rahman, I.A.
Stewart, S.E.
Zamora, S.
Powiązania:
https://bibliotekanauki.pl/articles/945494.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Echinodermata
Ctenocystoidea
evolution
bilateral symmetry
Ordovician
ctenocystoid
Upper Ordovician
United Kingdom
bilateral body
echinoderm
Opis:
During the early Palaeozoic, echinoderm body plans were much more diverse than they are today, displaying four distinct types of symmetry. This included the bilateral ctenocystoids, which were long thought to be restricted to the Cambrian. Here, we describe a new species of ctenocystoid from the Upper Ordovician of Scotland (Conollia sporranoides sp. nov.). This allows us to revise the genus Conollia, which was previously based on a single poorly-known species from the Upper Ordovician of Wales (Conollia staffordi). Both these species are characterized by a unique morphology consisting of an elongate-ovoid body covered in spines, which clearly distinguishes them from their better-known Cambrian relatives; they are interpreted as infaunal or semi-infaunal burrowers from deep-water environments. This indicates that the ctenocystoid body plan was not fixed early in the evolution of the group, and they most likely modified their structure as an adaptation to a new mode of life in the Ordovician.
Źródło:
Acta Palaeontologica Polonica; 2015, 60, 1; 39-48
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Propagation of threatened climber species Entada rheedii Spreng. – a medicinal plant with extremely thick and hard seed coat
Autorzy:
Hossain, M.A.
Dey, J.
Rahman, M.A.
Powiązania:
https://bibliotekanauki.pl/articles/2078264.pdf
Data publikacji:
2021
Wydawca:
Polska Akademia Nauk. Instytut Dendrologii PAN
Tematy:
Entada rheedii
germination potential
growth performance
pre-sowing treatments
rooting abil-
ity
rooted cuttings
Opis:
The study explored propagation techniques of Entada rheedii Spreng., a threatened medicinal climber species with extremely hard seed coat. Propagation trials included both pre-sowing treatments of seeds for germination and clonal propagation by stem cutting. Pre-sowing treatments included (a) soaking of both cut (notched) and uncut (intact) seeds in water for 0 h, 24 h, 48 h, and 72 h and (b) immersion of intact seeds in 5% acetone solution for 5 min, 10 min, and 20 min before sowing in germination media in polybags. On the other hand, stem cutting involved treating the summer or autumn cuttings with 0%, 0.4%, and 0.8% IBA solution before rooting in non-mist propagator. Notched seeds soaked in water for 48 h showed the fastest seed germination with the highest germination percentages (73.3) and better seedling growth in terms of plant height, collar diameter, leaf number and total dry mass followed by notched seeds soaked in water for 72 h. The slowest germination and the lowest germination percentage (3.3), as well as the poorest growth performance was for intact seeds without any treatment. The highest rooting percent- age with maximum number of roots (36.6) was obtained from the summer cuttings treated with 0.4% IBA solution followed by autumn cuttings with 0.8% IBA and the lowest (43.3% and 8.3 roots) was for summer cuttings in control. The factors also dictated the survival and growth performance of rooted cuttings in the nursery conditions. The outcomes of these trials i.e., notched seeds soaking in water for 48 h will help to enhance the propagation of this valuable medicinal plant species.
Źródło:
Dendrobiology; 2021, 85; 92-104
1641-1307
Pojawia się w:
Dendrobiology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Response of non-linear shock absorbers-boundary value problem analysis
Autorzy:
Rahman, M. A.
Ahmed, U.
Uddin, M. S.
Powiązania:
https://bibliotekanauki.pl/articles/265424.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet Zielonogórski. Oficyna Wydawnicza
Tematy:
amortyzator
tłumik drgań
stabilność
wartość graniczna
shock absorber
untuned vibration damper
frequency ratios
non-linear springs
non-linear dampers
stability
boundary value problem
multisegment method of integration
Opis:
A nonlinear boundary value problem of two degrees-of-freedom (DOF) untuned vibration damper systems using nonlinear springs and dampers has been numerically studied. As far as untuned damper is concerned, sixteen different combinations of linear and nonlinear springs and dampers have been comprehensively analyzed taking into account transient terms. For different cases, a comparative study is made for response versus time for different spring and damper types at three important frequency ratios: one at r = 1, one at r > 1 and one at r <1. The response of the system is changed because of the spring and damper nonlinearities; the change is different for different cases. Accordingly, an initially stable absorber may become unstable with time and vice versa. The analysis also shows that higher nonlinearity terms make the system more unstable. Numerical simulation includes transient vibrations. Although problems are much more complicated compared to those for a tuned absorber, a comparison of the results generated by the present numerical scheme with the exact one shows quite a reasonable agreement.
Źródło:
International Journal of Applied Mechanics and Engineering; 2013, 18, 3; 793-814
1734-4492
2353-9003
Pojawia się w:
International Journal of Applied Mechanics and Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Distributed generation’s integration planning involving growth load models by means of genetic algorithm
Autorzy:
Rahman, Y. A.
Manjang, S.
Yusran, A.
Ilham, A.
Powiązania:
https://bibliotekanauki.pl/articles/141167.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
distributed generation
genetic algorithm
load models
power loss
load growth
Opis:
The growth in the system load accompanied by an increase of power loss in the distribution system. Distributed generation (DG) is an important identity in the electric power sector that substantially overcomes power loss and voltage drop problems when it is coordinated with a location and size properly. In this study, the DG integration into the network is optimally distributed by considering the load conditions in different load models used to surmount the impact of load growth. There are five load models tested namely constant, residential, industrial, commercial and mixed loads. The growth of the electrical load is modeled for the base year up to the fifth year as a short-term plan. Minimization of system power loss is taken as the main objective function considering voltage limits. Determination of the location and size of DG is optimally done by using the breeder genetic algorithm (BGA). The proposed studies were applied to the IEEE 30 radial distribution system with single and multiple placement DG scenarios. The results indicated that installing an optimal location and size DG could have a strong potential to reduce power loss and to secure future energy demand of load models. Also, commercial load requires the largest DG active injection power to maintain the voltage value within tolerable limits up to five years.
Źródło:
Archives of Electrical Engineering; 2018, 67, 3; 667--682
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Measurement of radioactive impact of the gas well accident on environment of Sylhet division in Bangladesh
Autorzy:
Chakraborty, S. R.
Saha, K. K.
Rahman, A. K. M. R.
Kamal, M.
Chowdhury, M. I.
Alam, Md. K.
Powiązania:
https://bibliotekanauki.pl/articles/411611.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Natural gas well accident
Environmental radioactivity
Public exposure etc
Opis:
The main goal of this study is to carry out the public exposure contribution from radioactive materials occurring due to the accident of natural gas exploration well of Sylhet division in Bangladesh. This study has been performed by using a gamma spectrometry of Genie 2000 software embedded PC-based High Purity Germanium (HPGe) detector system. The measured activity concentrations of naturally occurring radionuclides 232Th, 226Ra, and 40K have been in the public safety limit on the environment of the study areas. The specific activity of detected anthropogenic radionuclide 137Cs has been found to be very little with a mean value of 1.65 ± 0.61 and 1.13 ± 0.57 Bq•kg–1 in the Magurchhera and Haripur gas field area respectively.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 9, 1; 48-60
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of Radiological Dose around a 3-MW TRIGA Mark-II Research Reactor
Autorzy:
Rahman, A. F. M. M.
Shamsuzzaman, M.
Rahman, M. S.
Uddin, K.
Yeasmin, S.
Nazmul, Haque H. M.
Akramuzzaman, M. M.
Chakraborty, S. R
Powiązania:
https://bibliotekanauki.pl/articles/412377.pdf
Data publikacji:
2013
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
source term
release rate
TRIGA Mark-II reactor
dispersion
ingestion and deposition of radionuclide
Gaussian plume model
dose calculations
Opis:
A hypothetical accidental case of a 3-MW TRIGA Mark-II research reactor has been assumed to assess the radiological consequences due to the deposition of 137Cs and 90Sr on ground, vegetation, milk and meat. The air concentrations in sixteen cardinal directions have been estimated where the maximum concentration has been found to be at 110 m distance from the core of the reactor for all the directions. Calculated maximum doses of 137Cs, 90Sr and both 137Cs and 90Sr have been found to be within the ranges of 0.005-0.014 μSv hr–1, 0.013-0.036 μSv hr–1 and 0.018-0.05 μSv hr–1, respectively for all the directions, which are below the measured background dose limit 0.25 μSv hr–1 and also within the IAEA acceptable dose rate limit of 0.5 μSv hr–1. The calculated low doses due to the aforementioned radionuclides can be considered negligible with regard to the radiation hazards. The relationship between total effective dose rate for various pathways (i.e. immersion, inhalation, ground deposition, and ingestion of contaminated vegetation, milk, meat) and air concentration in all the directions has been established. Obtained relation reveals that the total effective dose rate is directly proportional to the air concentration, and the overall proportionality constants for 137Cs and 90Sr radionuclides have been obtained as 0.57 and 0.28, respectively. This study might provide information on the radiological safety required for the radiation protection purposes of the people living in the vicinity of the reactor site.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2013, 10, 2; 183-200
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Optimization of fresh palm oil mill effluent biodegradation with Aspergillus niger and Trichoderma virens
Autorzy:
Jalaludin, N.
Rahman, R. A.
Razali, F.
Barghash, H. F. A.
Sukri, S. S. M.
Powiązania:
https://bibliotekanauki.pl/articles/204704.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Aspergillus niger
optimization
POME
palm oil mill effluent
Trichoderma virens
Opis:
In this work, response surface optimization strategy was employed to enhance the biodegradation process of fresh palm oil mill effluent (POME) by Aspergillus niger and Trichoderma virens. A central composite design (CCD) combined with response surface methodology (RSM) were employed to study the effects of three independent variables: inoculum size (%), agitation rate (rpm) and temperature (°C) on the biodegradation processes and production of biosolids enriched with fungal biomass protein. The results achieved using A. niger were compared to those obtained using T. virens. The optimal conditions for the biodegradation processes in terms of total suspended solids (TSS), turbidity, chemical oxygen demand (COD), specific resistance to filtration (SRF) and production of biosolids enriched with fungal biomass protein in fresh POME treated with A. niger and T. virens have been predicted by multiple response optimization and verified experimentally at 19% (v/v) inoculum size, 100 rpm, 30.2°C and 5% (v/v) inoculum size, 100 rpm, 33.3°C respectively. As disclosed by ANOVA and response surface plots, the effects of inoculum size and agitation rate on fresh POME treatment process by both fungal strains were significant.
Źródło:
Archives of Environmental Protection; 2016, 42, 1; 63-73
2083-4772
2083-4810
Pojawia się w:
Archives of Environmental Protection
Dostawca treści:
Biblioteka Nauki
Artykuł

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